A few months back now we bought a Garmin 67LMT navigation unit. Garmin make not a bad product in general and is a popular brand when you start researching into GPS's. The Garmin is certainly better than the android apps we were using. I does still have a fair few annoyances with this model than what i had hoped for. But for the most part it does get us to our destinations eventually.
We have decided to call the voice behind the navigation "Doris". Doris was about to part our company one day when she lead us down a street with a 2.7m high bridge and our caravan is 3 meters high. Granted she's not to know that but we did have the fun times of having to back a caravan up a S bend hill for about 200 meters to take a alternative route.
Overall Doris generally does ok, shes got alot of places to remember :). So i won't throw her out the window just yet. Garmin do release updates via the web which i plug the Nav unit into the PC and update it so improvements are always happening. Just a little disappointing that the maps aren't as good as you'd expect for this day and age.
You can read a similar blog about this from here Larry's blog on navigation units